use std::collections::HashSet;
use std::ffi::CStr;
use std::os::raw::c_void;

use vulkanalia::vk::ExtDebugUtilsExtension;
use vulkanalia::window as vk_window;
use vulkanalia::{prelude::v1_0::*, Version};

use winit::window::Window;

use log::*;

use anyhow::{anyhow, Result};

use crate::app::{AppData, VALIDATION_ENABLED, VALIDATION_LAYER};

const PORTABILITY_MACOS_VERSION: Version = Version::new(1, 3, 216);

extern "system" fn debug_callback(
    severity: vk::DebugUtilsMessageSeverityFlagsEXT,
    type_: vk::DebugUtilsMessageTypeFlagsEXT,
    data: *const vk::DebugUtilsMessengerCallbackDataEXT,
    _: *mut c_void,
) -> vk::Bool32 {
    let data = unsafe { *data };
    let message = unsafe { CStr::from_ptr(data.message) }.to_string_lossy();

    if severity >= vk::DebugUtilsMessageSeverityFlagsEXT::ERROR {
        error!("({:?}) {}", type_, message);
    } else if severity >= vk::DebugUtilsMessageSeverityFlagsEXT::WARNING {
        warn!("({:?}) {}", type_, message);
    } else if severity >= vk::DebugUtilsMessageSeverityFlagsEXT::INFO {
        debug!("({:?}) {}", type_, message);
    } else {
        trace!("({:?}) {}", type_, message);
    }

    vk::FALSE
}

pub(crate) unsafe fn create_instance(
    window: &Window,
    entry: &Entry,
    data: &mut AppData,
) -> Result<Instance> {
    let application_info = vk::ApplicationInfo::builder()
        .application_name(b"Vulkan Tutorial\0")
        .application_version(vk::make_version(1, 0, 0))
        .engine_name(b"No Engine\0")
        .engine_version(vk::make_version(1, 0, 0))
        .api_version(vk::make_version(1, 0, 0));

    let available_layers = entry
        .enumerate_instance_layer_properties()?
        .iter()
        .map(|l| l.layer_name)
        .collect::<HashSet<_>>();

    if VALIDATION_ENABLED && !available_layers.contains(&VALIDATION_LAYER) {
        return Err(anyhow!("Validation layer requested but not supported."));
    }

    let layers = if VALIDATION_ENABLED {
        vec![VALIDATION_LAYER.as_ptr()]
    } else {
        Vec::new()
    };

    let mut extensions = vk_window::get_required_instance_extensions(window)
        .iter()
        .map(|e| e.as_ptr())
        .collect::<Vec<_>>();

    let flags = if cfg!(target_os = "macos") && entry.version()? >= PORTABILITY_MACOS_VERSION {
        info!("Enabling extensions for macOS portability.");
        extensions.push(
            vk::KHR_GET_PHYSICAL_DEVICE_PROPERTIES2_EXTENSION
                .name
                .as_ptr(),
        );
        extensions.push(vk::KHR_PORTABILITY_ENUMERATION_EXTENSION.name.as_ptr());
        vk::InstanceCreateFlags::ENUMERATE_PORTABILITY_KHR
    } else {
        vk::InstanceCreateFlags::empty()
    };

    if VALIDATION_ENABLED {
        extensions.push(vk::EXT_DEBUG_UTILS_EXTENSION.name.as_ptr());
    }

    let mut info = vk::InstanceCreateInfo::builder()
        .application_info(&application_info)
        .enabled_layer_names(&layers)
        .enabled_extension_names(&extensions)
        .flags(flags);

    let mut debug_info = vk::DebugUtilsMessengerCreateInfoEXT::builder()
        .message_severity(vk::DebugUtilsMessageSeverityFlagsEXT::all())
        .message_type(vk::DebugUtilsMessageTypeFlagsEXT::all())
        .user_callback(Some(debug_callback));

    if VALIDATION_ENABLED {
        info = info.push_next(&mut debug_info);
    }

    let instance = entry.create_instance(&info, None)?;

    if VALIDATION_ENABLED {
        let debug_info = vk::DebugUtilsMessengerCreateInfoEXT::builder()
            .message_severity(vk::DebugUtilsMessageSeverityFlagsEXT::all())
            .message_type(vk::DebugUtilsMessageTypeFlagsEXT::all())
            .user_callback(Some(debug_callback));

        data.messenger = instance.create_debug_utils_messenger_ext(&debug_info, None)?;
    }

    Ok(instance)
}